Well, from the background articles it seems that people aren't so much as hearing it as they are noticing a lack of wildlife and associating the two.
Given the CP-140 is expressly designed for hunting things under the ocean that wish to stay hidden, I'm sure we'll learn the source soon enough. While the Air Force is saying it only searched for an hour and a half, the Aurora can search areas for upwards of 8 hours at a time, so I highly doubt that's all they are planning on doing up there.
Given the CP-140 is expressly designed for hunting things under the ocean that wish to stay hidden, I'm sure we'll learn the source soon enough. While the Air Force is saying it only searched for an hour and a half, the Aurora can search areas for upwards of 8 hours at a time, so I highly doubt that's all they are planning on doing up there.